Optical power calibration at the outer edge of an optical storage carrier

ABSTRACT

A CD-R/RW drive (optical storage carrier player) includes an access device for writing data on a CD (optical storage carrier). The CD includes a central portion, an inner power calibration area which can provide the optical power calibration 100 times, a data storage area for data writing by a user and a last possible lead-out area, in order from CD center to CD outer edge. The method is to define an outer power calibration area in the last possible lead-out area to perform optical power calibration in this outer power calibration area such that the total number of optical power calibrations for the CD can exceed 100.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method of optical powercalibration performed by the optical storage carrier player, such as theCD-R/RW drive, and more particularly, to a method of optical powercalibration where calibration is performed at the outer edge of anoptical storage carrier, such as a compact disc (CD).

[0003] 2. Description of the Prior Art

[0004] CD-R and CD-RW drives (optical storage carrier player) now arepopular PC peripherals. In general, the CD-R/CD-RW drive performs anoptical power calibration before actually writing data onto a compactdisc (CD, optical storage carrier), such as: CD-R/CD-RW disc. Thepurpose of the optical power calibration is to determine a optimizedwriting optical power. Typical optical power calibration involveswriting information to a power calibration area (PCA), which is locatedclosed to the central portion of a CD disc. This information written onthe power calibration area through the power calibration is read back,and the CD-R/CD-RW drive determines an optimized optical power from thesignal reflected from the CD disc, and then the CD-R/CD-RW drive writesfurther data onto the CD disc by applying the optimized optical power.

[0005] Please refer to FIG. 1. FIG. 1 is a side view of a CD 10. The CDis a thin circular disk that is symmetrical about a centerline 11. TheCD's specification is given in the Orange Book. The CD 10 comprises acentral portion 12, a Power Calibration area (PCA) 14, located outsidethe central portion 12, a data storage area 16, located outside the PCA14, and a last possible lead-out area 18, located near the CD outeredge.

[0006] Please refer to FIG. 2. FIG. 2 is a perspective view of the PCA14 shown in FIG. 1. The PCA 14 comprises a test area 20 which allows atest data written thereon during the power calibration, and a count area22 in which a count of the number of power calibrations alreadyperformed in the PCA 14 is recorded. According to the specification inthe Orange Book, the test area 20 and the count area 22 are divided into100 partitions 20 a, 22 a, respectively. Therefore, the optical powercalibration can be performed up to 100 times.

[0007] However, after the CD disc is unloaded from the tray or the trayis moving out once, at least one optical power calibration is necessaryto be performed for starting a new data writing action. According to theCD-disc standard described in the Orange Cook, the 100 partitionsavailable on the PCA limit the number of times available for writing toCD-R disc.

SUMMARY OF THE INVENTION

[0008] It is therefore one aspect of the present invention to provide amethod of optical power calibration in which calibration is performed atthe outer edge of a CD, increasing the number of times optical powercalibration can be performed.

[0009] According to one aspect of the invention, a method of opticalpower calibration comprises the following steps:

[0010] step 1: provide data to be written;

[0011] step 2: control the access device to perform an optical powercalibration in the outer power calibration area;

[0012] step 3: according to an optical power calibration result,determine the writing optical power; and

[0013] step 4: control the access device to write the information on theCD.

[0014] Another aspect of the invention further provides a CD-R/RW drive.The drive has an access device for writing data on a CD. The CDcomprises a central portion, an inner power calibration area, locatedoutside the central portion, a data storage area, located outside theinner power calibration area, and an outer power calibration area,located outside the data storage area.

[0015] A still further aspect of the invention further provides acontrol apparatus that controls a CD-R/RW drive. The control apparatuscontrols the access device to perform optical power calibration in theouter power calibration area to determine a optimized optical power,then writing information on the CD, according to the optimized opticalpower.

[0016] Another aspect of the invention provides a CD. The CD has acentral portion, an inner power calibration area, located outside thecentral portion, a data storage area, located outside the inner powercalibration area, and an outer power calibration area, located outsidethe data storage area The outer power calibration area is used toperform an optical power calibration to determine an optimized opticalpower.

[0017] It is one advantage of various embodiments of the presentinvention that the calibration method with calibration in the outer edgeof a CD can be performed in both the PCA and the last possible lead-outarea, so that optical power calibration can be performed over 100 times.

[0018] These and other aspects of the present invention will no doubtbecome apparent to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment which isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a side view of a CD according to the prior art.

[0020]FIG. 2 is a perspective view of a Power Calibration area as shownin FIG. 1.

[0021]FIG. 3 is a perspective view of a CD-R/RW drive according to thepresent invention.

[0022]FIG. 4 is a perspective view of an optical power calibrationperformed in a last possible lead-out area.

[0023]FIG. 5 is a flow chart of the optical power calibration accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] Please refer to FIG. 3. FIG. 3 is a perspective view of a CD-R/RWdrive 30, according to the present invention. The CD-R/RW drive 30comprises an access device 32 and a control apparatus 36. The accessdevice 32 reads data from and writes data onto the CD 34. The controlapparatus 36 controls the access device 32 to perform optical powercalibration and to write data on the CD 34, according to the calibrationresult.

[0025] The CD 34 is a thin disk with symmetry about a centerline 31. Therelated specifications and functionality of the CD 34 can be found inthe Orange Book. From the center toward the outer edge, the CD 34comprises a central portion 38, an inner power calibration area 40, adata storage area 46, and a last possible lead-out area 48. The centralportion 38 comprises a center hole and a clamping area. The inner powercalibration area 40 allows for 100 optical power calibrations. The CD 34further comprises a program memory area (PMA) and a lead-in area (notshown). Both areas are located between the inner power calibration area40 and the data storage area 46.

[0026] According to the standard specification described in the OrangeBook, the CD's outer edge should reserve a predetermined length of datatrack corresponding to at least one and a half minutes (01:30:00) atnormal playing speed. This area (the length of data track mentionedabove) is the so-called last possible lead-out area 48 of the CD 34. Thestarting point of the last possible lead-out area 48 is called a lastpossible start time 50. Typically, right after termination of a datawriting action, the CD-R/RW drive 34 will immediately write an endingmessage into the lead-out area 48.

[0027] Please refer to FIG. 4. FIG. 4 is a perspective view of theoptical power calibration performed in the last possible lead-out area48. A prior art CD-R/RW drive performs optical power calibration in theinner power calibration area 40. However, according to the presentinvention, an outer power calibration area 52 is defined in the lastpossible lead-out area 48, so that an optical power calibration can beperformed in the outer power calibration area 52.

[0028] As shown in FIG.4, the outer power calibration area 52 comprisesa test area 54 for allowing the test data written thereon during thepower calibration and a count area 56 for recording a number count ofthe power calibrations already performed in the outer power calibrationarea 52. In an implementation example according to the presentinvention, the test area 54 and the count area 56 are divided into 100partitions 54 a, 56 a, respectively.

[0029] Typically, 15 frames are necessary for performing each opticalpower calibration. Therefore, 1500 frames are necessary for performing100 optical power calibrations. The 1500 frames are corresponding to20-second period (00:20:00) at the normal playing speed of a CD-R/RWdrive. According to the CD specification described in the Orange Book,the length of the last possible lead-out area 48 of a CD should be atleast corresponding to one and a half minutes (01:30:00) at the normalplaying speed. Moreover, some manufacturers supply CDs where the lengthof the last possible lead-out area 48 is 01:50:00 which is much longerthan the 20 seconds which correspond to 100 optical power calibrations.So, if it is possible to reserve enough length of the last possiblelead-cut area 48 for recording the ending messages of a CD, then theextra length of the last possible lead-out area 48 may be used foroptical power calibration.

[0030] As shown in FIG.4, according to the present implementation, thepredetermined length separation 66 is disposed between the startingpoint 58 of the outer power calibration area 52 and the last possiblestart time 50 (the starting point of the last possible lead-out area48). The predetermined length separation 66 is reserved at least 1minute (01:00:00), which is long enough for recording the endingmessage. There is enough length of data track left in the lead-cut area48 for defining an outer power calibration area of at least 20-second(00:20:00) period, which is long enough for performing 100 optical powercalibrations.

[0031] Please refer to FIG. 5. FIG. 5 is a flow chart of an opticalpower calibration according to the present invention. The method ofoptical power calibration according to the present invention comprisesthe following steps:

[0032] Step 100: provide data to be written;

[0033] Step 102: determine the number of optical power calibrations thathave been performed on the CD 34;

[0034] Step 104: if the number of optical power calibrations is lessthan 100, control the access device 32 to perform the calibration in theinner power calibration area 40 in FIG. 3, else perform the calibrationin the outer power calibration area 52.

[0035] Step 106: according to the calibration result, determine theoptimized optical power, and then control the access device 32 to writefurther information to the CD 34.

[0036] It should be noted that even though the step order of thecalibration procedure mentioned above performs calibration in the innerpower calibration area 40 first, then performs calibration in the outerpower calibration area 52, this order is still arbitrary. The relativeposition between the outer power calibration area 52 and the lastpossible lead-out area 48 is for example only. In fact, a requirementaccording to many embodiments of the present invention is that the setup of the outer power calibration area 52 should not obstruct thefunction of the last possible lead-out area 48.

[0037] In contrast to the prior art, where optical power calibration isonly performed in the inner power calibration area 40, the presentinvention provides a method of optical power calibration withcalibration in the outer edge of a CD. Calibration takes place in boththe inner power calibration area 40 and in the outer power calibrationarea 52, so that more calibrations may be performed on a CD.

[0038] Those skilled in the art will readily observe that numerousmodifications and alterations of the method may be made while retainingthe teachings of the invention. Accordingly, the above disclosure shouldbe construed as limited only by the metes and bounds of the appendedclaims.

what is claimed is:
 1. A method of optical power calibration forcalibrating a writing optical power of an optical storage carrierplayer, the optical storage carrier player comprising an access devicefor writing data onto an optical storage carrier, the optical storagecarrier comprising a central portion, a data storage area locatedoutside the central portion, and an outer power calibration area locatedoutside the data storage area, the method comprising steps of: (a)theaccess device performing an optical power calibration in the outer powercalibration area to determine an optimized optical power; and (b) theaccess device writing the data onto the data storage area by applyingthe optimized optical power.
 2. The method of optical power calibrationof claim 1 wherein the optical storage carrier further comprises a lastpossible lead-out area located near an outer edge of the optical storagecarrier for recording ending information, and the outer powercalibration area is located within the last possible lead-out area. 3.The method of optical power calibration of claim 2 wherein the lastpossible lead-out area comprises a predetermined length separationdisposed between a starting point of the outer power calibration areafrom a starting point of the last possible lead-out area.
 4. The methodof optical power calibration of claim 3 wherein the predetermined lengthseparation corresponds to at least 1 minute period at a normal playingspeed.
 5. The method of optical power calibration of claim 1 wherein alength of the outer power calibration area is corresponding to at least20 second period at a normal playing speed.
 6. The method of opticalpower calibration of claim 1 wherein the outer power calibration areafurther comprises a test area for allowing a test data written thereonduring the power calibration, and a count area for recording a numbercount of power calibrations already performed on the outer powercalibration area.
 7. The method of optical power calibration of claim 1wherein the optical storage carrier further comprises an inner powercalibration area located close to the central portion, and the innerpower calibration area comprises a count area for recording a numbercount of the optical power calibrations already performed within theinner power calibration area, the method further comprises step beforethe step (a): performing the optical power calibration in the innerpower calibration area if the number count is less than a predeterminednumber of power calibrations capable of being performed in the innerpower calibration area, and then skipping the step (a).
 8. An opticalstorage carrier player for accessing an optical storage carrier, theoptical storage carrier comprising a central portion, a data storagearea located outside the central portion, and an outer power calibrationarea located outside the data storage area, the optical storage carrierplayer comprising: an access device for writing data on an opticalstorage carrier; and a control apparatus for controlling the accessdevice to perform an optical power calibration in the outer powercalibration area to determine an optimized optical power.
 9. The opticalstorage carrier player of claim 8 wherein the optical storage carrierfurther comprises a last possible lead-out area located near an outeredge of the optical storage carrier for recording ending information,and the outer power calibration area is located within the last possiblelead-out area.
 10. The optical storage carrier player of claim 9 whereina predetermined length separation is disposed between a starting pointof the outer power calibration area and a starting point of the lastpossible lead-out area.
 11. The optical storage carrier player of claim10 wherein the predetermined length separation corresponds to at least 1minute period at a normal playing speed.
 12. The optical storage carrierplayer of claim 8 wherein a length of the outer power calibration areacorresponds to at least 20 second period at a normal playing speed. 13.The optical storage carrier player of claim 8 wherein the outer powercalibration area further comprises a test area for allowing a test datawritten thereon during the power calibration and a count area forrecording a number count of the power calibration already performed onthe outer power calibration area.
 14. The optical storage carrier playerof claim 8 wherein the optical storage carrier further comprises aninner power calibration area located close to the central portion, andthe inner power calibration area comprises a count area for recoding anumber count of the optical power calibrations already performed in theinner calibration area; when the number count is less than apredetermined number, the access device performs the optical powercalibration in the inner power calibration area instead of the outerpower calibration area.
 15. A optical storage carrier comprising: acentral portion; a data storage area located close to the centralportion for writing data; and an outer power calibration area locatedoutside the data storage area for performing an optical powercalibration to determine an optimized optical power.
 16. The opticalstorage carrier of claim 15 further comprises a last possible lead-outarea located near the outer edge of the optical storage carrier forrecording ending information, and the outer power calibration area islocated within the last possible lead-out area.
 17. The optical storagecarrier of claim 16 wherein a predetermined length separation disposedbetween a starting point of the outer power calibration area from astarting point of the last possible lead-out area.
 18. The opticalstorage carrier of claim 17 wherein the predetermined length separationcorresponds to at least 1 minute period at a normal playing speed. 19.The optical storage carrier of claim 15 wherein a length of the outerpower calibration area corresponds to at least 20 seconds period at anormal playing speed.
 20. The optical storage carrier of claim 15wherein the outer power calibration area comprises a test area forallowing a test data written thereon during the power calibration, and acount area for recording a number count of power calibrations alreadyperformed on the outer power calibration area.
 21. The optical storagecarrier of claim 15 wherein the optical storage carrier furthercomprises an inner power calibration area located closer to the centralportion than the data storage area.